CN1084908C - Method and apparatus for tracing controlling in video tape recorder - Google Patents
Method and apparatus for tracing controlling in video tape recorder Download PDFInfo
- Publication number
- CN1084908C CN1084908C CN94108900A CN94108900A CN1084908C CN 1084908 C CN1084908 C CN 1084908C CN 94108900 A CN94108900 A CN 94108900A CN 94108900 A CN94108900 A CN 94108900A CN 1084908 C CN1084908 C CN 1084908C
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- China
- Prior art keywords
- aforementioned
- signal
- capstan
- track part
- rate controlled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- 238000000034 method Methods 0.000 title claims description 15
- 230000008676 import Effects 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims 1
- 230000005055 memory storage Effects 0.000 claims 1
- 238000005516 engineering process Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000005452 bending Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000005021 gait Effects 0.000 description 1
- 230000011218 segmentation Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B21/00—Head arrangements not specific to the method of recording or reproducing
- G11B21/02—Driving or moving of heads
- G11B21/08—Track changing or selecting during transducing operation
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/18—Driving; Starting; Stopping; Arrangements for control or regulation thereof
- G11B15/46—Controlling, regulating, or indicating speed
- G11B15/467—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven
- G11B15/4673—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the tape while the head is rotating
- G11B15/4675—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the tape while the head is rotating with provision for information tracking
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/18—Driving; Starting; Stopping; Arrangements for control or regulation thereof
- G11B15/46—Controlling, regulating, or indicating speed
- G11B15/467—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven
- G11B15/4673—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the tape while the head is rotating
- G11B15/4675—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the tape while the head is rotating with provision for information tracking
- G11B15/4676—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the tape while the head is rotating with provision for information tracking using signals recorded in tracks disposed in parallel with the scanning direction
- G11B15/4677—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the tape while the head is rotating with provision for information tracking using signals recorded in tracks disposed in parallel with the scanning direction using auxiliary signals, i.e. pilot signals
- G11B15/4678—Controlling, regulating, or indicating speed in arrangements for recording or reproducing wherein both record carriers and heads are driven by controlling the speed of the tape while the head is rotating with provision for information tracking using signals recorded in tracks disposed in parallel with the scanning direction using auxiliary signals, i.e. pilot signals superimposed on the main signal track
Abstract
The invention provides a tracking control art of the pilot signals recorded in the video tape recorder, which includes a memory for storing tracking control information of a previous track corresponding to a present position of a current track being tracking-controlled, and a tracking controller for generating a new tracking control signal by using a tracking error signal derived from the current track and stored tracking control information for the previous track, to thereby enhance the precision of tracking control of the present track even when the track is deformed.
Description
The present invention relates to the tracking and controlling method and the device thereof of video tape recorder, particularly make magnetic head operate in the tracking and controlling method and the device thereof of the video tape recorder on the track part of regulation exactly with the revolution of leading shaft motor with by the tracking error that magnetic head detects.
In the technology of relevant video tape recorder (VTR), tracking Control is that video head operates in exactly on the track part of regulation and obtains maximum envelope output.In order to carry out tracking Control, be ahead of at magnetic head under the situation of regulation track part, with regard to the rotating speed that slows down leading shaft motor the gait of march of tape is slowed down, the speed of then accelerating leading shaft motor when magnetic head lags track part makes tape accelerate to advance.
For carrying out such tracking Control, must detect tracking error.The VTR of Video Home System (VHS) is recorded in control signal on the linear track, and 8mmVTR is then in order to be recorded in pilot signal on the track part from motion tracking (calling ATF in the following text).Under the situation of the 8mmVTR that uses pilot signal, be to use the pilot signal of the different regulation number of frequency, and calculate tracking error with the pilot signal that detects at playback time the track part segmentation of recording image signal.Followingly illustrate that according to Fig. 1 and Fig. 2 reducing the tracking error control head operates in original device on the track part exactly.
Fig. 1 is the block scheme of the original follow-up control apparatus of expression.In the device of Fig. 1, tracking control unit 21 inputs produce the 1st control signal C of the control capstan speed relevant with the speed of magnetic drum (not shown) from the tracking error signal TE of tracking error signal generator (not shown)
1Leading shaft motor 23 makes the capstan rotation that is used for transmitting magnetic drum, and leading shaft motor driver 24 produces the drive signal of leading shaft motors 23, is added on the capstan speed control 22 corresponding to the frequency signal (calling the FG signal in the following text) of the revolution of leading shaft motor 23.22 outputs of capstan commentaries on classics degree controller make the 2nd control signal C of capstan with certain speed rotation with the FG signal
2Totalizer 25 is the output signal C of tracking control unit 21
1Output signal C with capstan speed control 22
2Addition outputs to leading shaft motor driver 24 then.
Fig. 2 A represents along the desirable track part and the magnetic head run trace H of diagonal line arrangement, and Fig. 2 B is illustrated in the tracking error signal TE that is detected by the magnetic head walking under the replay mode.
Fig. 3 A represents along the track of the magnetic head of straight line moving on the crooked track part, and Fig. 3 B represents the tracking error that straightaway magnetic head detects from the track part of bending with similar shape.The normal track part that forms is the sort of shape shown in Fig. 2 A, i.e. the linear that is parallel to each other along the diagonal of tape, still, if the linearity of track part subside and bend to Fig. 3 A at that rate, crooked track part just information by crooked shape store.Therefore, if read in the information that writes down on such track part, shown in Fig. 3 B, tracking error will have the similar size that produces repeatedly.Fig. 1 device tracking Control during read output signal from the video-tape with this non-linear track part is described as follows.
The tracking error signal TE that tracking control unit 21 inputs are obtained by pilot signal.Produce the 1st control signal C
1, the rotational speed of the FG calculated signals motor 24 that capstan speed control 22 usefulness are sent here from leading shaft motor 24 compares the rotating speed of the leading shaft motor 24 set and the rotating speed that calculates and to produce the 2nd control signal C
2, totalizer 25 is aforesaid control signal C
1, C
2Addition produces the 3rd control signal C
3And output.According to the 3rd control signal C
3Drive leading shaft motor 24, and tracking error TE and from the revolution signal FG of leading shaft motor 24 as continuous tracking Control.But, FG signal with tracking error signal TE and leading shaft motor 24 produces the speed control signal that magnetic head is followed the tracks of usefulness, can produce some mistimings when driving leading shaft motor according to the speed control signal that is produced again, that is: the position on the track part of in fact tracked control lags behind than the position that is detected tracking error.Therefore, can not carry out correct tracking Control, especially under the situation that the track part degree of crook is big, tracking Control is just difficult more.Thereby produce the problem of the quality deterioration of the image that is shown.Make under the situation that track part narrows down for carrying out high density recording, problem is just more outstanding like this.
The technology that the track part of bending is correctly followed the tracks of is authorized in people's such as three bridges the U.S. Pat 5,182,683 open on January 26th, 1993.In this technology, earlier the signal that reads by magnetic head is carried out envelope detection from track part, be converted into digital envelope then, and the drive controlling capstan makes the intensity of digital envelope reach actual maximal value.Simultaneously, the desirable scanning patter of digital envelope and the magnetic head of storage in advance relatively, and the position that changes magnetic head makes the intensity of envelope signal become actual maximal value for the direction of actual rotating shaft perpendicular to rotary head drum.
Other parameter technology of control tape operation are the U.S. Pat 4,581,659 of authorizing people such as Azuma on April 8th, 1986.The technology of this Patent publish is to adjust the setting value of leading shaft motor control usefulness again with the difference of the tracking error signal of the tracking error signal of track part at that time and front track part.
Even the purpose of this invention is to provide a kind of under the situation that the linearity of track part is subside and track width be compressed under the situation about narrowing down also the correctly method of tracking Control, this method be for the tracking Control information stores of the front track part of each position of a plurality of tracking Control position of Gao Ding on each track part in storer, use corresponding to the tracking Control information of the front track part of each tracking Control position of wanting tracking Control at that time and carry out the tracking Control of track part at that time.
The tracking Control information stores of each front, position track part that another object of the present invention provides a kind of a plurality of tracking Control position of setting on outspoken for the magnetic of being subside in linearity is in storer and use corresponding to the tracking Control information of the front track part of each tracking Control position of wanting tracking Control at that time and carry out the device of the tracking Control of track part at that time.
That realizes above the object of the invention produces the 1st capstan speed control signal for the revolution of the capstan that divides the tracking and controlling method of reading the information that is recorded the track part of segment record to comprise the steps: the signal of revolution at that time of comparison of aforementioned capstan according to pilot signal and set from leading shaft-driven tape; Storage is corresponding to the 2nd capstan speed control signal of the front track part of each position of a plurality of control positions on the track part; Produce tracking error signal from pilot signal; Input is also upgraded among aforementioned tracking error signal and aforementioned stored the 2nd tracking velocity control signal, corresponding to the 2nd tracking velocity control signal of aforementioned tracking error signal; And the 1st addition step of exporting after aforementioned the 2nd tracking velocity control signal that is updated and the 1st capstan speed control signal addition.
Realize other purpose of the present invention for from leading shaft-driven tape, dividing the follow-up control apparatus of reading the information that is recorded the track part of segment record to comprise according to pilot signal: import aforementioned capstan revolution signal, output is compared capstan revolution and the revolution set and the capstan speed control of the 1st capstan speed control signal that produces; Input pilot signal and produce the tracking error generator of tracking error signal; The storer of the 2nd capstan speed control signal that storage generates corresponding to each position of a plurality of control positions on the track part; Input is from the tracking control unit that with corresponding the 2nd tracking velocity control signal of aforementioned tracking error signal it is upgraded back output in the 2nd tracking velocity control signal of storing in the tracking error signal of this tracking error generator of preceding art and the input store; The totalizer of exporting after the 2nd capstan speed control signal addition from the 1st capstan speed control signal of aforementioned capstan speed control and aforementioned renewal; And the output signal of importing aforementioned totalizer drives the rotating driver of aforementioned capstan rotation.
Below describe an embodiment of specific implementation tracking and controlling method of the present invention and device with reference to the accompanying drawings in detail.
Fig. 1 is the block scheme of original follow-up control apparatus.
Fig. 2 A and Fig. 2 B are the run trace of expression magnetic head and the synoptic diagram of tracking error.
Fig. 3 A and Fig. 3 B are the linearity track parts of subsideing and by the key diagram of the detected tracking error of this track part.
Fig. 4 is the block scheme of expression according to the tracking means of the VTR of the preferred embodiments of the present invention.
Fig. 5 is the precedence diagram of explanation tracking and controlling method of the present invention.
Fig. 4 represents the follow-up control apparatus according to the VTR of the preferred embodiments of the present invention.
The device of Fig. 4 is provided with the prime amplifier 32 that is connected with video head, input produce the ATF processor 33 of tracking error signal TE and the output signal of ATF processor 33 carried out outputing to after mould/transformation of variables tracking control unit 35 from the vision signal of prime amplifier 32 A/D transducer 34.In addition, the device of Fig. 4 includes generation produces the 1st capstan speed control signal CAP corresponding to the revolution signal FG1 of the tracking control unit 35 of the 2nd capstan speed control signal STC of a plurality of tracing positionals of having set, the storer 36 of storing the 2nd capstan speed control signal STC that is generated by tracking control unit 35 and input leading shaft motor 31 capstan speed control 37.The 1st totalizer 39 outputs to leading shaft motor driver 38 after the 1st capstan speed control signal CAP and the 2nd capstan speed control signal STC addition.
The device that the following describes Fig. 4 is the tracking Control action during the playback of video signal from the tape with crooked track part.
The vision signal that is recorded is read out by video head by the driving of leading shaft motor 31 and unshowned magnetic drum, if the vision signal that is read out is input to prime amplifier 32, prime amplifier 32 outputs to ATF processor 33 after just input signal being amplified.ATF processor 33 bolt from incoming video signal goes out pilot signal, and generates tracking error signal TE with the pilot signal that detects.The tracking error signal TE that is transformed to digital signal by A/D transducer 34 is imported into tracking control unit 35, and the tracking error signal TE of processor 351 inputs produces the 3rd capstan speed control system signal corresponding to present tracking Control position.At this moment, the revolution data FG2 of the magnetic drum motor that processor 351 usefulness are transfused to and track part starting point signal PG determine the control position of present track part, and processor 351 is read the 2nd capstan speed control signal corresponding to track part before the present control position from storer 36.At this, storer 36 is stored in corresponding separately tracking Control position to the 2nd capstan speed control signal of former track part in advance.The 2nd totalizer 352 is added up the 2nd capstan speed control signal of the 3rd capstan speed control signal and former track part, the 2nd capstan speed control signal STC of the present track part that addition is obtained is stored in the storer 36 again, outputs to simultaneously in the 1st totalizer 39.On the other hand, the same with the capstan speed control 22 of Fig. 1, capstan speed that capstan speed control 37 usefulness have been set and revolution signal FG produce the 1st capstan speed control signal CAP.The 1st totalizer 39 produces actual capstan speed control signal RTC to the 2nd capstan speed control signal ST the 1st capstan speed control signal CAP addition of track part now, and outputs to leading shaft motor driver 38.As previously mentioned, the generation of aforesaid actual capstan control signal RTC is that the whole control positions that will carry out tracking Control are carried out.And the 2nd capstan speed control signal of the existing track part of storage is used as the tracking Control of next bar track part in the storer 36.
Therefore, owing to the capstan speed control signal of handle corresponding to the former track part of the control position of present track part is used on the control position of present track part, so can more correctly carry out tracking Control.
Fig. 5 is the precedence diagram of explanation tracking and controlling method of the present invention.The tracking and controlling method of the present invention that illustrates on Fig. 5 is that the microprocessor that the output signal with the A/D transducer 34 of input Fig. 4 is connected with revolution signal FG1 from leading shaft motor 31 is realized.That is to say that this microprocessor has system's identical functions of being made up of tracking control unit 35, capstan speed control 37 and the 1st totalizer 39 in the follow-up control apparatus with Fig. 4.
Under replay mode, VTR moves at the beginning, and microprocessor is with regard to initializes memory 36 (step 100).That is: storage is corresponding to the 2nd capstan speed control signal STC of the last track part of each control position of the present track part that will carry out tracking Control.Judge whether it is tracking Control pattern (step 110), if the tracking Control pattern, microprocessor just reads the tracking error signal TF (step 120) that is separated by ATF processor 33.Each control position that microprocessor is wanted tracking Control according to the revolution FG2 of magnetic drum motor and track part starting point signal PG decision, and with the 3rd capstan speed control signal (step 120) of the tracking error signal TE generation that is transfused to present control position.Microprocessor control store 35 is so that from the 2nd capstan speed control signal of storer 36 outputs corresponding to first track part of the present track position that will control, if the 2nd capstan speed control signal the 3rd capstan speed control signal addition of aforesaid last track part is produced the 2nd capstan speed control signal of present track part, there is at this moment the 2nd capstan speed control signal STC in the storer 36 (step 140) in microprocessor with regard to control store 36.And the 1st capstan speed control signal that microprocessor determines the revolution by leading shaft motor is added up with the 2nd capstan speed detection signal of present track part and is generated actual capstan speed control signal RTC (step 150).Actual capstan speed control signal control leading shaft motor driver 38 according to from the microprocessor input drives leading shaft motor 31 (step 160).Tracking Control one to assigned position finishes, and just carries out the tracking Control of next tracking Control position with aforesaid method.
As mentioned above, the present invention is owing to the tracking Control information with last track part, so even under the situation that track part is deformed, also can improve the accuracy to the tracking Control of present track part.
Claims (7)
1. follow-up control apparatus for the information of reading the track part record that is recorded on the leading shaft-driven tape is characterized in that comprising:
Import the revolution signal of aforementioned capstan, output is capstan revolution and the revolution set and produce the capstan rate controller of the 1st capstan rate controlled signal relatively;
The input pilot signal produces the tracking error generator of tracking error signal;
The storer of the 2nd capstan rate controlled signal that storage generates corresponding to each position of a plurality of control positions on the track part;
Input among the 2nd capstan rate controlled signal of storing in the tracking error signal of aforementioned tracking error generator, input and the updated stored device with corresponding the 2nd capstan rate controlled signal, Shu Chu the tracking control unit then of aforementioned tracking error signal;
First adder from output after the 2nd capstan rate controlled signal plus of the 1st capstan rate controlled signal of aforementioned capstan rate controller and aforementioned renewal; With
The output signal of importing aforementioned first adder drives the rotating driver of aforementioned capstan rotation.
2. according to the follow-up control apparatus of claim 1, it is characterized in that the 2nd capstan rate controlled signal of aforementioned memory storage for whole control positions of last track part.
3. according to the follow-up control apparatus of claim 1, it is characterized in that aforesaid tracking control unit comprises:
Input is transformed to the A/D transducer of numerical data from the tracking error signal of aforementioned tracking error generator and with it;
Input is from the digital tracking error signal of aforementioned A/D transducer, corresponding to present control position, difference by the last track part and the degree of crook of present track part produces the 3rd capstan rate controlled signal, controls the processor of aforementioned memory for the 2nd capstan rate controlled signal of the corresponding aforementioned present control position of output from aforementioned memory; With
The 2nd totalizer of exporting behind the 3rd capstan control signal of aforementioned processing device output and the 2nd guide shaft rate controlled signal plus from the corresponding last track part of aforementioned memory.
4. according to the follow-up control apparatus of claim 3, it is characterized in that the aforementioned processing device is for controlling aforementioned memory to the output signal of aforementioned the 2nd totalizer corresponding to appropriate location storage in storer.
5. the tracking and controlling method for the information that track part write down of playback record on leading shaft-driven tape comprises:
Import aforementioned capstan revolution signal, comparison of aforementioned capstan revolution signal and the capstan revolution of having set, and produce the control signal output step that the 1st capstan rate controlled signal is exported then;
The tracking error that the input pilot signal produces tracking error signal produces step;
The 2nd capstan rate controlled signal that storage generates corresponding to each position of a plurality of control positions on the track part;
Importing aforementioned tracking error produces among tracking error signal that step produces and aforementioned stored the 2nd capstan rate controlled signal of input corresponding to the 2nd capstan rate controlled signal of aforementioned tracking error signal and is upgraded the step of exporting then; With
The 1st addition step of exporting behind aforementioned the 2nd capstan rate controlled signal that is updated and aforementioned the 1st capstan rate controlled signal plus,
Import the output signal of aforementioned the 1st addition step and the step that the aforementioned capstan of it driving is rotated.
6. according to the tracking and controlling method of claim 5, it is characterized in that the 2nd capstan rate controlled signal of aforesaid storing step storage corresponding to the control position of last track part.
7. according to the tracking and controlling method of claim 6, it is characterized in that aforesaid renewal output step comprises:
Aforementioned tracking error signal is transformed to numerical data;
Import the digital tracking error signal after the aforementioned A/D conversion, corresponding to control position now by last track part and now the pass of the degree of crook of track part produce the 3rd capstan rate controlled signal;
Read in aforementioned stored the 2nd capstan rate controlled signal the 2nd capstan rate controlled signal corresponding to the last track part of aforementioned present control position; And
The 2nd addition step of exporting after aforementioned the 3rd capstan rate controlled signal and aforementioned the 2nd capstan rate signal addition to last track part of reading.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10977/93 | 1993-06-16 | ||
| KR1019930010977A KR0148139B1 (en) | 1993-06-16 | 1993-06-16 | Tracking control method & apparatus of video tape recorder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1109996A CN1109996A (en) | 1995-10-11 |
| CN1084908C true CN1084908C (en) | 2002-05-15 |
Family
ID=19357490
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN94108900A Expired - Fee Related CN1084908C (en) | 1993-06-16 | 1994-06-16 | Method and apparatus for tracing controlling in video tape recorder |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5589997A (en) |
| JP (1) | JP2941652B2 (en) |
| KR (1) | KR0148139B1 (en) |
| CN (1) | CN1084908C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR0147344B1 (en) * | 1995-01-28 | 1998-10-15 | 구자홍 | Capstan phase control method for vcr |
| KR0152045B1 (en) * | 1995-04-27 | 1998-10-15 | 김광호 | Variable speed reproduction apparatus of digital vcr |
| JP3538585B2 (en) * | 2000-04-13 | 2004-06-14 | オリオン電機株式会社 | Tape drive |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4581659A (en) * | 1982-12-24 | 1986-04-08 | Hitachi, Ltd. | Method and apparatus for reproducing information at variable speeds from a magnetic tape |
| US5182683A (en) * | 1989-07-18 | 1993-01-26 | Mitsubishi Denki Kabushiki Kaisha | Position control of a magnetic head in a magnetic recording and reproducing system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4947272A (en) * | 1987-03-30 | 1990-08-07 | Pioneer Electronic Corporation | Signal reproducing device which offsets the tracking error signal for a digital tape player |
| US5119249A (en) * | 1988-09-22 | 1992-06-02 | Nakamichi Corporation | Tracking error detection circuit using pilot signals during tape reproduction |
| US5280399A (en) * | 1988-10-25 | 1994-01-18 | Canon Kabushiki Kaisha | Video signal recording apparatus |
-
1993
- 1993-06-16 KR KR1019930010977A patent/KR0148139B1/en not_active IP Right Cessation
-
1994
- 1994-06-16 JP JP13443694A patent/JP2941652B2/en not_active Expired - Fee Related
- 1994-06-16 CN CN94108900A patent/CN1084908C/en not_active Expired - Fee Related
- 1994-06-16 US US08/260,825 patent/US5589997A/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4581659A (en) * | 1982-12-24 | 1986-04-08 | Hitachi, Ltd. | Method and apparatus for reproducing information at variable speeds from a magnetic tape |
| US5182683A (en) * | 1989-07-18 | 1993-01-26 | Mitsubishi Denki Kabushiki Kaisha | Position control of a magnetic head in a magnetic recording and reproducing system |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2941652B2 (en) | 1999-08-25 |
| KR0148139B1 (en) | 1998-10-15 |
| KR950001735A (en) | 1995-01-03 |
| CN1109996A (en) | 1995-10-11 |
| JPH0773546A (en) | 1995-03-17 |
| US5589997A (en) | 1996-12-31 |
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Granted publication date: 20020515 |